1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// UNSUPPORTED: c++03, c++11, c++14, c++17
10
11#include <algorithm>
12#include <cstddef>
13#include <deque>
14#include <iterator>
15#include <list>
16#include <string>
17#include <vector>
18
19#include "benchmark/benchmark.h"
20#include "../../GenerateInput.h"
21
22int main(int argc, char** argv) {
23 auto std_generate_n = [](auto out, auto n, auto f) { return std::generate_n(out, n, f); };
24
25 // {std,ranges}::generate_n
26 {
27 auto bm = []<class Container>(std::string name, auto generate_n) {
28 benchmark::RegisterBenchmark(
29 name,
30 [generate_n](auto& st) {
31 std::size_t const size = st.range(0);
32 Container c(size);
33 using ValueType = typename Container::value_type;
34 ValueType x = Generate<ValueType>::random();
35
36 for ([[maybe_unused]] auto _ : st) {
37 benchmark::DoNotOptimize(c);
38 generate_n(c.begin(), size, [&x] {
39 benchmark::DoNotOptimize(x);
40 return x;
41 });
42 benchmark::DoNotOptimize(c);
43 }
44 })
45 ->Arg(32)
46 ->Arg(50) // non power-of-two
47 ->Arg(1024)
48 ->Arg(8192);
49 };
50 bm.operator()<std::vector<int>>(name: "std::generate_n(vector<int>)", generate_n: std_generate_n);
51 bm.operator()<std::deque<int>>(name: "std::generate_n(deque<int>)", generate_n: std_generate_n);
52 bm.operator()<std::list<int>>(name: "std::generate_n(list<int>)", generate_n: std_generate_n);
53 bm.operator()<std::vector<int>>("rng::generate_n(vector<int>)", std::ranges::generate_n);
54 bm.operator()<std::deque<int>>("rng::generate_n(deque<int>)", std::ranges::generate_n);
55 bm.operator()<std::list<int>>("rng::generate_n(list<int>)", std::ranges::generate_n);
56 }
57
58 benchmark::Initialize(&argc, argv);
59 benchmark::RunSpecifiedBenchmarks();
60 benchmark::Shutdown();
61 return 0;
62}
63

source code of libcxx/test/benchmarks/algorithms/modifying/generate_n.bench.cpp